My favorite way to cook sweet potatoes and yams, most root vegetables actually, is roasting them in the oven. Roasting them means I don't have to do much chopping or preparation. I can throw them in the oven and go workout on our elliptical, or catch up on things around the house. Plus, they become sweeter than if you boiled them.
What I do:
Preheat the oven to 375°C. I wash the yams and sweet potatoes and cut out eyes if needed. If the ends are really skinny like these ones, I cut them off, if they are rounded, I leave them on. I find the skinny ones easier to cut with the ends off. Then I cut them in half length wise and place them face down on a baking sheet lined with parchment paper. Like so:
Roast for 25-35 minutes depending on the size of yams. Large ones may need 45 min up to an hour. These took 30 minutes.
I love how they get a little caramelized in spots.
I topped the sweet potatoes and yams with steamed kale & peas. For seasoning the greens I used nutritional yeast, Mrs. Dash and garlic powder.